I couldn't tell you where the line is drawn between 'Artistic Nudes' and Porn, I suppose Google or Wikipedia will have an answer but I'd rather think it through myself to be honest.
I suppose you could say that that Porn is intended to arouse the viewer, that that is it's very purpose, any additional artistic merit or increased production values are purely incidental.
Artistic Nudes (very much capitalised) on the other hand are a study of the human form in all it's beauty, a more intellectual or artistic exercise perhaps..
This being said, I'm not sure that my Mum, or indeed my Wife or my Boss (also all very much capitalised!), would be entirely convinced by me looking at too much of
either.
Met-Art certainly straddle the two mediums with great style. Unashamedly a pay-to-view porn site but with incredibly high production values and amazing photography.
And in the end, perhaps, all this pigeonholing is unnecessary. I would take stab at guessing that women are the most photographed subjects on dA, both clothed and unclothed. Rightly so, for they are surely the subjects most worthy of photographing.
Below are three brilliant photographs that contain naked or nearly naked women.
We Moved In Silence 2 by `hakanphotographyAlone by ~eugenebuzukMlle D. - ch. by ~Renoux